• Effects of carbon monoxide
• S+S CO poisoning

Mech:

• binds to Hb with 200x greater affinity than O2 → decreases O2 content in blood
  • PaO2 still stays normal (dissolved oxygen); carotid body receptors respond to P1O2, so stimulation may be stimulated later, when metabolic acidosis triggers other centers
• shifts the oxy-dissociation curve left → changes shape from sigmoidal to hyperbolic → causes O2 to release at lower-than-normal tissue oxygen levels
• tissue hypoxia leads to inc CBF, CSF pressure, and cerebral capillary permeability, causing cerebral edema

S+S: headache, weakness, dizziness, dyspnea, N, V, confusion, blurred vision, loss of consciousness, red skin colour

• patients with severe poisoning are vulnerable to pressure trauma to skin, subQ tissue, muscle esp at sites supporting body weight or pinned under objects → pain and muscle breakdown with myoglobin deposition can occur

Management:

• see below; don’t forget Co-oximeter is possible

• Half-life of CO is 4 hours on room air, 1 hour if 100% O2 and <30 min on hyperbaric oxygen at 2 to 3 atmospheres

• if severe metabolic acidosis with normal carboxyhemoglobin and methemoglobin, consider cyanide poisoning;

  • has short half-life of 1h; consider cyanokit

  

  

Complications:

• Permanent neurologic sequelae - CNS symptoms e.g. HA, mood disorder, personality change persisting for ≥ 3 months
• Delayed neurologic sequelae - recover with treatment then have board spectrum or neurologic and psychiatric abnormalities days to weeks after exposure

Discharge:

• No resp distress
• Normal mentation
• Normal CO level